Carton forming machine

ABSTRACT

A machine for forming a tubular carton from a generally rectangular flat sidewall blank having thermoplastic coatings thereon and comprising a sidewall blank magazine, a heating station, a forming mandrel, and means for withdrawing a blank from the magazine and conveying the withdrawn blank through the heating station to the forming mandrel is improved by incorporating a hold down mechanism to maintain the position of the withdrawn blank on the conveying means, utlizing hot gas from perforated conduits to head only the margins of the blank in the heating station, and employing a forming mandrel coated with a poly(arylene sulfide) coating composition. The forming machine can be employed in combination with a filling and sealing machine having at least one conveyor with means for properly positioning the cartons in the conveyor, means for intermittently driving the conveyor in accurately reproducible movements, filling means, means for heating the top sealing panels with hot gas, means for sealing the filled and heated cartons, and means for removing the filled and sealed carton from the conveyor. These improvements enable the machine to be operated at higher production speeds, while permitting a reduction in the size of the overall machine.

United States Patent [1 1 Farfaglia et al.

[ June 24, 1975 CARTON FORMING MACHINE [73] Assignee: Phillips Petroleum Company,

Bartlesville, Okla.

[22] Filed: Sept. 7, 1973 [21] Appl. No.: 395,037

52 u.s.c|.....; ..53/183;53/266;53/375; 93/441 GT; 93/010. 1 51 Int. Cl ..B65b 3/02 [58] Field of Search 93/44.'1 R, 44.1 GT, DIG. 1, 93/392, 36R, 49 R, 56 R, 53 R, 53 SD; 53/183, 266, 375

[56] References Cited UNITED STATES PATENTS 2,726,583 12/1955 Barnes et a1. 93144.1 R 3,354,129 11/1967 Edmonds, Jr. et a1. 260/79 3,392,458 7/1968 Braun 93/441 R 3,788,917 1/1974 Linda 93/36 PC X Primary Examiner-Roy Lake Assistant Examiner-James F. Coan ABSTRACT A machine for forming a tubular carton from a generally rectangular flat sidewall blank having thermoplastic coatings thereon and comprising a sidewall blank magazine, a heating station, a forming mandrel, and

means for withdrawing a blank. from the magazine and conveying the withdrawn blank through the heating station to the forming mandrel is improved by incorporating a hold down mechanism to maintain the position of the withdrawn blank on the conveying means, utlizing hot gas from perforated conduits to head only the margins of the blank in the heating station, and employing a forming mandrel coated with a poly(arylene sulfide) coating composition. The forming machine can be employed in combination with a filling and sealing machine having at least one conveyor with means for properly positioning the cartons in the conveyor, means for intermittently driving the conveyor in accurately reproducible movements, filling means, means for heating the top sealing panels with hot gas, means for sealing the filled and heated cartons, and means for removing the filled and sealed carton from the conveyor. These improvements enable the machine to be operated at higher production speeds, while permitting a reduction in the size of the overall machine.

45 Claims, 56 Drawing Figures PATENTEDJUN24|915 3,890,765 SHEET 1 Q QOQQ PATENTEIJJUM 24 I975 SHEET SHEET PATENTEIJJUN 24 I975 mw Mn 51 PATENTEDJUN 24 I975 SHEET a I w FIG. 6

PATENTEIJJUM24 1975 3,890,765

SHEET 8 FIG. 8

PATENTEDJUN 24 ms E5 9 O 7 6 5 SHEET 9 g FIG. /0

FIG.

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- PATENTEDJUN24 ms 50.765

FIG. 2/

/ FIG. 20

PATENTEDJUN24 I975 3,890,765

sum 1 5 FIG. 22

PMEWEEJUNM I975 13; 890 765 will PATENTEDJUN 24 ms 3 .8 9O 76 5 SHEET 1 s FIGZS SATENTEDMMM 197s 3.890.765

SHEET 1'3 

1. A machine for forming a tubular carton from a generally rectangular flat sidewall blank having thermoplastic coatings on the upper and lower surfaces thereof and having first and second side margins and top and bottom margins, which comprises a forming mandrel, means for wrapping said sidewall blank around said forming mandrel to overlap said first and second side margins thereof, a conveying means having a conveyor run on which said blank is to be transported through a heating station to said forming mandrel, said conveying means having means for engaging a blank deposited on said conveyor run, a supply magazine means for containing a plurality of said blanks, transfer means for successively withdrawing individual blanks from said supply magazine means and for depositing each thus withdrawn individual blank on said conveyor run, holding means for maintaining the position to the thus deposited blank on said conveyor run until after the thus deposited blank is contacted by said means for engaging, means for actuating said holding means to contact said thus withdrawn individual blank as the blank is being deposited on said conveyor run, means for periodically activating said conveying means, means for actuating said transfer means during the time said conveying means is inactive, a first conduit means positioned in said heating station at least generally parallel to and spaced generally upwardly from the location which would be occupied by the upper surface of the first side margin of the blank in said heating station, said first conduit means having orifices therein spaced along the length thereof and directed at the location which would be occupied by said upper surface of said first side margin of the blank in said heating station, a second conduit means positioned in said heating station at least generally parallel to and spaced generally downwardly from the location which would be occupied by the lower surface of the second side margin of the blank in said heating station, said second conduit means having orifices therein spaced along the length thereof and directed at the location which would be occupied by the lower surface of said second side margin of the blank in said heating station, and means for supplying a hot gas to said first and second conduit means.
 2. A machine in accordance with claim 1 further comprising means for mounting said supply magazine means over said conveyor run; and wherein said transfer means comprises at least one suction cup, means mounted beneath said conveyor run adapted to move said at least one suction cup upwardly through said conveyor run into engaging contact with the bottom one of said blanks in said supply magazine means and then to return said at least one suction cup downwardly through said conveyor run to deposit the withdrawn blank on said conveyor run, and means for maintaining a vacuum in said at least one suction cup from the time said at least one suction cup contacts the bottom blank in said supply magazine means to the time the withdrawn blank is deposited on said conveyor run; wherein the First and second side margins of the blanks in said supply magazine means extend generally in the direction of movement of said conveyor run; and wherein said holding means comprises first and second holddown means, said first hold-down means being positioned to engage the upper surface of the first side margin of the blank being deposited on said conveyor run and said second hold-down means being positioned to engage the upper surface of the second side margin of the blank being deposited on said conveyor run.
 3. A machine in accordance with claim 2 wherein said means for actuating said holding means comprises a first pair of horizontally positioned shafts, means for mounting said first hold-down means on one of said first pair of shafts for rotation therewith, means for mounting said second hold-down means on the other of said first pair of shafts for rotation therewith, a second pair of vertically positioned shafts, first and second vertically positioned sleeves, one of said second pair of shafts being positioned within and extending above said first sleeve, the other of said second pair of shafts being positioned within and extending above said second sleeve, each of said second pair of shafts having a clevis block secured to the upper end thereof and being provided with a spring positioned between and under compression by the respective clevis block and the respective sleeve, each of said second pair of shafts having a vertically extending slot therein, each of said sleeves having a pin therein extending through the slot of the associated one of said second pair of shafts to permit relative motion between each of said sleeves and the associated vertical shaft to the extent of the slot in the associated vertical shaft, means responsive to the generally vertical movement of one of said clevis blocks for rotating said one of said first pair of shafts, means responsive to the generally vertical movement of the other of said clevis blocks for rotating said other of said first pair of shafts, and means for moving said first and second sleeves at least generally vertically responsive to the vertical movement of said at least one suction cup.
 4. A machine in accordance with claim 3 further comprising third conduit means positioned in said heating station at least generally parallel to and spaced from the location which would be occupied by the upper surface of the bottom margin of the blank in said heating station, said third conduit means having orifices therein spaced along the length thereof and directed at the location which would be occupied by said upper surface of said bottom margin of the blank in said heating station, and means for supplying hot gas to said third conduit means, the initial orifice in one of said first and second conduit means being adjacent to the location which would be occupied by the top margin of the blank in said heating station and the initial orifice of the other of said first and second conduits being adjacent to the location which would be occupied by the bottom margin of the blank in said heating station.
 5. A machine in accordance with claim 1 wherein at least a major portion of the blank contacting surface of said mandrel is coated with a coating composition comprising a normally solid poly(arylene sulfide).
 6. A machine in accordance with claim 1 wherein said holding means comprises first and second hold-down means, said first hold-down means being positioned to engage the upper surface of the first side margin of the blank being deposited on said conveyor run and said second hold-down means being positioned to engage the upper surface of the second side margin of the blank being deposited on said conveyor run; and wherein said means for actuating said holding means comprising a first pair of horizontally positioned shafts, means for mounting said first hold-down means on one of said first pair of shafts for rotation therewith, means for mounting said second hold-down means on the other of said first pair of shafts for rOtation therewith, a second pair of vertically positioned shafts, means for moving said second pair of shafts at least generally vertically responsive to the vertical movement of said transfer means, means responsive to the generally vertical movement of one of said second pair of shafts for rotating said one of said first pair of shafts, and means responsive to the generally vertical movement of the other of said second pair of shafts for rotating said other of said first pair of shafts.
 7. A machine in accordance with claim 1 further comprising third conduit means positioned in said heating station at least generally parallel to and spaced from the location which would be occupied by one surface of the bottom margin of the blank in said heating station, said third conduit means having orifices therein spaced along the length thereof and directed at the location which would be occupied by said one surface of said bottom margin of the blank in said heating station, and means for supplying hot gas to said third conduit means.
 8. A machine in accordance with claim 7 wherein the initial orifice in one of said first and second conduit means is adjacent to the location which would be occupied by the top margin of the blank in said heating station and the initial orifice of the other of said first and second conduits is adjacent to the location which would be occupied by the bottom margin of the blank in said heating station.
 9. A machine in accordance with claim 8 wherein at least a major portion of the blank contacting surface of said mandrel is coated with a coating composition comprising a normally solid poly(arylene sulfide).
 10. A machine in accordance with claim 7 further comprising a fourth conduit means positioned between said supply magazine means and said heating station, said fourth conduit means having a series of orifices therein spaced along the length thereof to form an air curtain between said supply magazine means and said heating station, and means for providing cool gas to said fourth conduit means.
 11. A machine in accordance with claim 1 further comprising a third conduit means positioned between said supply magazine means and said heating station, said third conduit means having a series of orifices therein spaced along the length thereof to form an air curtain between said supply magazine means and said heating station, and means for providing cool gas to said third conduit means.
 12. A machine in accordance with claim 11 wherein said means for providing cool gas to said third conduit means is actuated only when the machine is actuated and said conveying means is deactuated.
 13. A machine in accordance with claim 4 wherein at least a major portion of the blank contacting surface of said mandrel is coated with a coating composition comprising a normally solid poly(arylene sulfide).
 14. A machine for forming a tubular carton from a generally rectangular flat sidewall blank having thermoplastic coatings on the upper and lower surfaces thereof and having first and second side margins and top and bottom margins, which comprises a forming mandrel, means for wrapping said sidewall blank around said forming mandrel to overlap said first and second side margins thereof, a conveying means having a conveyor run on which said blank is to be transported through a heating station to said forming mandrel, a supply magazine means for containing a plurality of said blanks, transfer means for successively withdrawing individual blanks from said supply magazine means and for depositing each thus withdrawn individual blank on said conveyor run, a first conduit means positioned in said heating station at least generally parallel to and spaced generally upwardly from the location which would be occupied by the upper surface of the first side margin of the blank in said heating station, said first conduit means having orifices therein spaced along the length thereof and directed at the location which would be occupied by said upper surface of said first siDe margin of the blank in said heating station, a second conduit means positioned in said heating station at least generally parallel to and spaced generally downwardly from the location which would be occupied by the lower surface of the second side margin of the blank in said heating station, said second conduit means having orifices therein spaced along the length thereof and directed at the location which would be occupied by the lower surface of said second side margin of the blank in said heating station, means for supplying a hot gas to said first and second conduit means, and at least a major portion of the blank contacting surface of said mandrel being coated with a coating composition comprising a normally solid poly(arylene sulfide).
 15. A machine in accordance with claim 14 wherein said mandrel comprises a hollow aluminum mandrel body and a steel end cap positioned on one end of said mandrel body, all of the blank contacting surfaces of said mandrel body being coated with a continuous layer of said coating composition.
 16. A machine in accordance with claim 15 further comprising a turret having a plurality of said mandrels positioned thereon with the elongated axis of each mandrel being in a plane perpendicular to the axis of rotation of said turret and extending radially with respect to said axis of rotation, and means for rotating said turret.
 17. A machine in accordance with claim 16 wherein said conveying means has means for engaging a blank deposited on said conveyor run; and further comprising holding means for maintaining the position of the blank being deposited on said conveyor run until after the thus deposited blank is contacted by said means for engaging, means for actuating said holding means to contact the blank withdrawn from said supply magazine means as the withdrawn blank is being deposited on said conveyor run.
 18. A machine in accordance with claim 17 wherein said coating composition comprises a normally solid poly(arylene sulfide), from about 0.5 to about 100 percent by weight titanium dioxide, based on the weight of poly(arylene sulfide), and from about 0.5 to about 75 percent by weight fluorocarbon polymer, based on the weight of poly(arylene sulfide).
 19. Apparatus in accordance with claim 6 further comprising a third conduit means positioned between said supply magazine means and said heating station, said third conduit means having a series of orifices therein spaced along the length thereof to form an air curtain between said supply magazine means and said heating station, and means for providing cool gas to said third conduit means.
 20. A machine in accordance with claim 9 further comprising a conveyor having a plurality of carton holders, each carton holder having first and second side walls connected by a back wall to form a generally U-shaped pocket, said conveyor having a transfer station, at least one filling station, a heating station, and at least one sealing station; an upstream guide wall means and a downstream guide wall means positioned adjacent said transfer station to guide a carton into the carton holder in said transfer station, means for withdrawing a carton from a mandrel on said turret and transferring the thus withdrawn carton between said upstream guide wall means and said downstream guide wall means into said carton holder in said transfer station, a positioning element pivotably mounted adjacent the edge of said downstream guide wall means closest to said conveyor whereby the carton inserted into the article holder in said transfer station is in contact with said positioning element as said conveyor commences to move said carton and its associated carton holder from said transfer station, and means for resiliently biasing said positioning element to force the carton into the desired position in the carton holder and to maintain the desired position and then to permit the carton and holder to be moved out of said transfer station by the conveyor, and Means for intermittently driving said conveyor.
 21. A machine in accordance with claim 20 wherein said means for intermittently driving said conveyor comprises a drive shaft, a first ratchet mounted on said drive shaft and secured thereto for rotation therewith and having teeth extending in a first direction, a second ratchet mounted on said drive shaft and secured thereto for rotation therewith and having teeth extending in the direction opposite to said first direction, at least one ratchet drive pawl, pawl support means for mounting said at least one ratchet drive pawl and adapted for rotation about the elongated axis of said drive shaft, means for resiliently urging said at least one ratchet drive pawl into engagement with the teeth of said first ratchet during the forward rotation of said pawl support means about the said elongated axis to rotate said first and second ratchets and said drive shaft during the forward rotation of said pawl support means, reciprocating means for driving said pawl support means forward and then backward in oscillatory rotative motion about said elongated axis, a pivotably mounted brake arm adapted to be rotated into contact with a tooth of said second ratchet during the forward rotation of said pawl support means, a striker arm resiliently mounted on said pawl support means and adapted to engage said brake arm and pivot said brake arm into contact with a tooth of said second ratchet during the final portion of the forward rotation of said pawl support means.
 22. A machine in accordance with claim 21 wherein said resiliently mounted striker arm is adapted to apply pressure to a tooth of said second ratchet to cause the driven tooth of said first ratchet to move back into contact with said ratchet drive pawl before the commencement of the backward motion of said pawl support means in the event that said first and second ratchets and said drive shaft continued to rotate after the end of the forward motion of said pawl support means.
 23. Apparatus in accordance with claim 22 further comprising an annular drive plate for driving said conveyor, said drive plate being positioned about said drive shaft for rotative movement free of the movement of said drive shaft, a clutch plate mounted on said drive shaft and secured thereto for rotation therewith, one of said drive plate and said clutch plate being provided with depressions in the surface thereof facing the other of said drive plate and said clutch plate, said other of said drive plate and said clutch plate being provided with pins for engaging said depressions, and means for resiliently mounting said pins so that a jamming of said conveyor will cause said pins to disengage from said depressions, thereby permitting said drive shaft to be indexed without rotating said drive plate, said depressions being uniformly spaced at intervals corresponding to the degree of rotation of said drive shaft for each forward movement of said pawl support means so that said pins will reengage said depressions only when said drive plate is in proper relationship with said drive shaft.
 24. A machine in accordance with claim 23 for forming, filling and sealing gable top cartons formed from said blanks, each of said blanks having score lines therein defining a gable top forming structure; means at said at least one filling station for introducing into each of said cartons the product to be packaged; means for braking the score lines in the gable top forming structure of each carton to form six ridge panels defining a six sided opening in each carton; and means located at said heating station for heating the six ridge panels, comprising a support base, means attached to a central portion of the lower surface of said support base to define a central plenum chamber having a continuous outer perforated wall which has six sections corresponding to the six sides of said opening in said carton, means attached to the peripheral portion of the lower surface of said support base to define an outer annular plenum chaMber having a continuous inner perforated wall with six sections corresponding to the six sides of said opening, said outer wall of said central plenum chamber and said inner wall of said outer plenum chamber forming an annular space adapted to receive therein the ridge panels of a prebroken gable top structure of a filled carton without contact between the carton and the heating head, means for introducing heated gas into said central plenum chamber and into said outer plenum chamber, said outer wall of said central plenum chamber having perforations therethrough spaced at intervals along the length of each of the six sections thereof for directing jets of heated gas at the inner surface of each of the six ridge panels of the carton being heated, said outer wall of said central plenum chamber being inclined downwardly from said support base and outwardly away from the vertical axis of the carton being heated so that said jets of heated gas strike the inner surfaces of said ridge panels at acute angles and are deflected upwardly out of the carton; and means at said at least one sealing station for applying pressure to the thus heated ridge panels of each carton to seal said opening.
 25. A machine in accordance with claim 24 wherein said conveyor has a carton removal station, and further comprising a continuously actuated conveyor having a carton receiving station located thereon; and carton transfer means for moving a carton from said carton removal station to said carton receiving station, said carton transfer means comprising one or more suction cups capable of producing a substantially air-tight seal with the surface of the carton to be transferred, vacuum supply means operably connected to said one or more suction cups, reciprocating means for moving said one or more suction cups between a first position in contact with the surface of a carton located in said carton removal station and a second position in contact with the surface of a carton located in said carton receiving station, and vacuum control means interposed between said vacuum supply means and said one or more suction cups to apply a vacuum to said one or more suction cups while said reciprocating means is in said first position and traveling between said first position and said second position and to interrupt the vacuum supply to said one or more suction cups while said reciprocating means is in said second position.
 26. Apparatus in accordance with claim 14 wherein the initial orifice in one of said first and second conduit means is adjacent the location which would be occupied by the top margin of the blank in said heating station and the initial orifice of the other of said first and second conduits is adjacent the location which would be occupied by the bottom margin of the blank in said heating station.
 27. Apparatus in accordance with claim 26 further comprising third conduit means positioned in said heating station at least generally parallel to and spaced from the location which would be occupied by one surface of the bottom margin of the blank in said heating station, said third conduit means having orifices therein spaced along the length thereof and directed at the location which would be occupied by said one surface of said bottom margin, and means for supplying hot gas to said third conduit means.
 28. Apparatus in accordance with claim 27 wherein said third conduit means has a partition therein at about the midpoint of the width of the blank in the heating station to form separate plenum chambers, and wherein said means for supplying hot gas to said third conduit means comprises means for supplying hot gas to each of said plenum chambers at locations remote from said partition.
 29. Apparatus in accordance with claim 16 further comprising third conduit means positioned in said heating station at least generally parallel to and spaced from the location which would be occupied by one surface of the bottom margin of the blank in said heating station, said third conduit means Having orifices therein spaced along the length thereof and directed at the location which would be occupied by said one surface of said bottom margin of the blank in said heating station, and means for supplying hot gas to said third conduit means.
 30. Apparatus in accordance with claim 29 further comprising means for periodically actuating the conveyor means for transporting the individual blanks through said heating station to index a blank into position with respect to said first, second and third conduit means, and wherein the initial orifice in one of said first and second conduit means is adjacent the location which would be occupied by the top margin of the blank in said heating station and the initial orifice of the other of said first and second conduits is adjacent the location which would be occupied by the bottom margin of the blank in said heating station.
 31. Apparatus in accordance with claim 30 wherein said third conduit means has a partition therein at about the midpoint of the width of the blank in the heating station to form separate plenum chambers, and wherein said means for supplying hot gas to said third conduit means comprises means for supplying hot gas to each of said plenum chambers at locations remote from said partition.
 32. Apparatus in accordance with claim 30 further comprising a fourth conduit means positioned between said supply magazine means and said heating station, said fourth conduit means having a series of orifices therein spaced along the length thereof to form an air curtain between said supply magazine means and said heating station, and means for providing cool gas to said fourth conduit means.
 33. Apparatus in accordance with claim 32 wherein said means for providing cool gas to said fourth conduit means is actuated only when the machine is actuated and said conveying means is deactuated.
 34. A machine in accordance with claim 14 wherein said coating composition comprises a normally solid poly(arylene sulfide), from about 0.5 to about 100 percent by weight titanium dioxide, based on the weight of poly(arylene sulfide), and from about 0.5 to about 75 percent by weight fluorocarbon polymer, based on the weight of poly(arylene sulfide).
 35. A machine in accordance with claim 7 wherein said coating composition comprises a normally solid poly(arylene sulfide), from about 0.5 to about 100 percent by weight titanium dioxide, based on the weight of poly(arylene sulfide), and from about 0.5 to about 75 percent by weight fluorocarbon polymer, based on the weight of poly(arylene sulfide).
 36. A machine in accordance with claim 8 wherein said coating composition comprises a normally solid poly(arylene sulfide), from about 0.5 to about 100 percent by weight titanium dioxide, based on the weight of poly(arylene sulfide), and from about 0.5 to about 75 percent by weight fluorocarbon polymer, based on the weight of poly(arylene sulfide).
 37. A machine in accordance with claim 6 further comprising third conduit means positioned in said heating station at least generally parallel to and spaced from the location which would be occupied by one surface of the bottom margin of the blank in said heating station, said third conduit means having orifices therein spaced along the length thereof and directed at the location which would be occupied by said one surface of said bottom margin, and means for supplying hot gas to said third conduit means; and further comprising means for periodically actuating the conveyor means for transporting the individual blanks through said heating station to index a blank into position with respect to said first, second and third conduit means.
 38. A machine in accordance with claim 37 further comprising a fourth conduit means positioned between said supply magazine means and said heating station, said fourth conduit means having a series of orifices therein spaced along the length thereof to form an air curtain betwEen said supply magazine means and said heating station, and means for providing cool gas to said fourth conduit means.
 39. A machine in accordance with claim 38 wherein said means for providing cool gas to said fourth conduit means is actuated only when the machine is actuated and said conveying means is deactuated.
 40. A machine in accordance with claim 8 further comprising a conveyor having a plurality of carton holders, each carton holder having first and second side walls connected by a back wall to form a generally U shaped pocket, said conveyor having a transfer station, at least one filling station, a heating station, and at least one sealing station; means for withdrawing a carton from a mandrel on said turret and transferring the thus withdrawn carton into said carton holder in said transfer station, and means for intermittently driving said conveyor.
 41. A machine in accordance with claim 40 further comprising an upstream guide wall means and a downstream guide wall means positioned adjacent said transfer station to guide a carton into the carton holder in said transfer station, a positioning element pivotably mounted adjacent the edge of said downstream guide wall means closest to said conveyor whereby the carton inserted into the article holder in said transfer station is in contact with said positioning element as said conveyor commences to move said carton and its associated carton holder from said transfer station, and means for resiliently biasing said positioning element to force the carton into the desired position in the carton holder and to maintain the desired position and then to permit the carton and holder to be moved out of said transfer station by the conveyor.
 42. A machine in accordance with claim 40 wherein said means for intermittently driving said conveyor comprises a drive shaft, a first ratchet mounted on said drive shaft and secured thereto for rotation therewith and having teeth extending in a first direction, a second ratchet mounted on said drive shaft and secured thereto for rotation therewith and having teeth extending in the direction opposite to said first direction, at least one ratchet drive pawl, pawl support means for mounting said at least one ratchet drive pawl and adapted for rotation about the elongated axis of said drive shaft, means for resiliently urging said at least one ratchet drive pawl into engagement with the teeth of said first ratchet during the forward rotation of said pawl support means about the said elongated axis to rotate said first and second ratchets and said drive shaft during the forward rotation of said pawl support means, reciprocating means for driving said pawl support means forward and then backward in oscillatory rotative motion about said elongated axis, a pivotably mounted brake arm adapted to be rotated into contact with a tooth of said second ratchet during the forward rotation of said pawl support means, a striker arm resiliently mounted on said pawl support means and adapted to engage said brake arm and pivot said brake arm into contact with a tooth of said second ratchet during the final portion of the forward rotation of said pawl support means.
 43. A machine in accordance with claim 42 wherein said resiliently mounted striker arm is adapted to apply pressure to a tooth of said second ratchet to cause the driven tooth of said first ratchet to move back into contact with said ratchet drive pawl before the commencement of the backward motion of said pawl support means in the event that said first and second ratchets and said drive shaft continued to rotate after the end of the forward motion of said pawl support means.
 44. A machine in accordance with claim 40 for forming, filling and sealing gable top cartons from said blanks, each of said blanks having score lines therein defining a gable top forming structure; means at said at least one filling station for introducing into each of said cartons the product to be packaged; means for breaking the score lines in the gable top formiNg structure of each carton to form six ridge panels defining a six sided opening in each carton; and means located at said heating station for heating the six ridge panels, comprising a support base, means attached to a central portion of the lower surface of said support base to define a central plenum chamber having a continuous outer perforated wall which has six sections corresponding to the six sides of said opening in said carton, means attached to the peripheral portion of the lower surface of said support base to define an outer annular plenum chamber having a continuous inner perforated wall with six sections corresponding to the six sides of said opening, said outer wall of said central plenum chamber and said inner wall of said outer plenum chamber forming an annular space adapted to receive therein the ridge panels of a prebroken gable top structure of a filled carton without contact between the carton and the heating head, means for introducing heated gas into said central plenum chamber and into said outer plenum chamber, said outer wall of said central plenum chamber having perforations therethrough spaced at intervals along the length of each of the six sections thereof for directing jets of heated gas at the inner surface of each of the six ridge panels of the carton being heated, said outer wall of said central plenum chamber being inclined downwardly from said support base and outwardly away from the vertical axis of the carton being heated so that said jets of heated gas strike the inner surfaces of said ridge panels at acute angles and are deflected upwardly out of the carton; and means at said at least one sealing station for applying pressure to the thus heated ridge panels of each carton to seal said opening.
 45. A machine in accordance with claim 40 wherein said conveyor has a carton removal station, and further comprising a continuously actuated conveyor having a carton receiving station located thereon; and carton transfer means for moving a carton from said carton removal station to said carton receiving station, said carton transfer means comprising one or more suction cups capable of producing a substantially air-tight seal with the surface of the carton to be transferred, vacuum supply means operably connected to said one or more suction cups, reciprocating means for moving said one or more suction cups between a first position in contact with the surface of a carton located in said carton removal station and a second position in contact with the surface of a carton located in said carton receiving station, and vacuum control means interposed between said vacuum supply means and said one or more suction cups to apply a vacuum to said one or more suction cups while said reciprocating means is in said first position and traveling between said first position and said second position and to interrupt the vacuum supply to said one or more suction cups while said reciprocating means is in said second position. 